A Business Logic vulnerability exists in SourceCodester Loan Management System v1.0 due to the lack of proper input validation.

published 2026-04-01 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-17897

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits: 0; none known

A Business Logic vulnerability exists in SourceCodester Loan Management System v1.0 due to the lack of proper input validation. The application allows administrators to define "Loan Plans" which determine the duration of a loan (in months). However, the backend fails to validate that the duration must be a positive integer. An attacker can submit a negative value for the months parameter. The system accepts this invalid data and creates a loan plan with a negative duration.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 7 mo ago (2026-04-01)

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativeMonths.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H

Classification

Weakness

CWE-20 Improper Input Validation

References

github.com /meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativeMonths.md
exploit, third-party-advisory

Sources

CVE List CVE-2026-30523
NVD CVE-2026-30523

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Summary